1. Field of the Invention
The present invention relates to a storage system and a storage control device.
2. Description of the Related Art
Many types of data controlled by for example, companies, hospitals, Government organizations, and other organizations, are managed by storage control devices. Storage control devices include for example a plurality of hard disks, and provide storage capacity based on a Redundant Array of Independent Disks (RAID) to a host computer (hereafter referred to as the host). As the amount of data controlled by companies and other organizations grows from day to day, the storage capacity of storage control devices can become insufficient. When the storage capacity becomes insufficient it is possible to deal with it by increasing the storage capacity by adding a new hard disk to the storage control device, or moving old data from the storage control device to a tape device or similar.
On the one hand the number of hosts using storage control devices is increasing. The number of hosts that can be connected to a storage control device is limited by the specification of the storage control device, so it is generally difficult to connect a number of hosts that exceeds the specification. Therefore, in this case it is possible to replace an existing storage control device to which few hosts can be connected with another storage control device to which many hosts can be connected, or, increase the number of storage control devices.
If the number of storage control devices is increased, data is moved from existing storage control devices to the newly added storage control devices. Then, using path switching software provided on the host or switches or similar, the host accesses the storage control device on which the desired data exists (Japanese Patent Application Laid-open No. 2005-353035).
In the conventional art described in the above document, each host must determine every time which storage control device of a plurality of storage control devices to access. Therefore it is necessary to carry out access path switching setting for each host, and so on, which takes time for managing the storage system. Also, it is necessary to install software to carry out switching of the access path on each host, which increases the cost of the storage system.